Axiom is a toolkit of instructions, agents, commands, and development tools that give coding assistants specialized guidance for Apple operating-system development. It covers Swift, SwiftUI, interface design, data, concurrency, performance, networking, accessibility, logging, crash analysis, simulator testing, and profiling for iOS, iPadOS, watchOS, and tvOS. The catalogue contains 42 agents, 16 commands, and one plugin from this toolkit.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add CharlesWiltgen/Axiom --skill axiom-concurrencygit clone --depth 1 https://github.com/CharlesWiltgen/AxiomWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/charleswiltgen/axiom/axiom-concurrency)<a href="https://agentmods.dev/skills/charleswiltgen/axiom/axiom-concurrency"><img src="https://agentmods.dev/badge/skills/charleswiltgen/axiom/axiom-concurrency/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/charleswiltgen/axiom/axiom-concurrency"><img src="https://agentmods.dev/badge/skills/charleswiltgen/axiom/axiom-concurrency.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk pass
- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00043 | $0.02651 |
| Opus 5 | $0.00022 | $0.01326 |
| Sonnet 5 | $0.00009 | $0.00530 |
| Haiku 4.5 | $0.00004 | $0.00265 |
Grade A, and why
axiom-concurrency scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 185 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Concurrency
You MUST use this skill for ANY concurrency, async/await, threading, or Swift 6 concurrency work.
Not on Claude Code? Where this router says "Launch
some-auditoragent", read that auditor's file in this suite and follow it inline — the same procedure, needing only file search and read.Available here:
skills/concurrency-auditor.md.Agents that need Bash — builds, tests, simulators, crash symbolication — stay Claude Code-only; there is no inline equivalent for those.
Quick Reference
| Symptom / Task | Reference |
|---|---|
| async/await patterns, @MainActor, actors | See skills/swift-concurrency.md |
| Data race errors, Sendable conformance | See skills/swift-concurrency.md |
| Swift 6 migration, @concurrent attribute | See skills/swift-concurrency.md |
| Actor definition, reentrancy, global actors | See skills/swift-concurrency-ref.md |
| Task/TaskGroup/cancellation API | See skills/swift-concurrency-ref.md |
| AsyncStream, continuations | See skills/swift-concurrency-ref.md |
| DispatchQueue → actor migration | See skills/swift-concurrency-ref.md |
| Mutex (iOS 18+), OSAllocatedUnfairLock | See skills/synchronization.md |
| Atomic types, lock vs actor decision | See skills/synchronization.md |
| MainActor.assumeIsolated | See skills/assume-isolated.md |
| @preconcurrency protocol conformances | See skills/assume-isolated.md |
| Legacy delegate callbacks | See skills/assume-isolated.md |
Warning-free build crashes with _dispatch_assert_queue_fail |
See skills/isolation-inheritance-diag.md |
Crash signature _swift_task_checkIsolatedSwift |
See skills/isolation-inheritance-diag.md |
Core Data context.perform runtime crash inside @MainActor class |
See skills/isolation-inheritance-diag.md |
Combine .map/.sink crash from receive(on:) placement |
See skills/isolation-inheritance-diag.md |
| Delegate method crash from isolation inheritance (CLLocationManager, NSDocument, AVAudioPlayerDelegate, WKNavigationDelegate, PHPhotoLibraryChangeObserver) | See skills/isolation-inheritance-diag.md |
PhotoKit performChanges block traps on PhotoKit's queue |
See skills/isolation-inheritance-diag.md |
| Actor reentrancy / stale state across await | See skills/isolation-inheritance-diag.md |
| Swift Concurrency Instruments template | See skills/concurrency-profiling.md |
| Actor contention diagnosis | See skills/concurrency-profiling.md |
| Thread pool exhaustion | See skills/concurrency-profiling.md |
What ships with it
7 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 6d ago First seen · 185 lines · 43 tokens per session scan A 2d2491ca9326
axiom-concurrency is a skill published in the GitHub repository CharlesWiltgen/Axiom (1,155 stars, last pushed 3d ago), licensed MIT. It adds 43 tokens to every session and 2,651 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-06.
Other skills, from other repositories
kotlin-specialist
Provides idiomatic Kotlin implementation patterns including coroutine concurrency, Flow stream handling, multiplatform architecture, Compose UI construction, Ktor server setup, and type-safe DSL design. Use when building Kotlin applications requiring coroutines, multiplatform development, or Android with Compose.…
swiftui-dev
Use this skill for SwiftUI development, architecture, structure, performance, and Apple native app profiling. It combines.
wax
Swift framework guidance for Wax on-device memory/RAG. Use when writing Swift code with the public Memory facade, experimental PhotoMemory / VideoMemory, BuiltInMultimodalEmbeddings, embedding providers, retrieval modes, or hybrid search. For agent operators using the Wax MCP server tools, use the separate wax-mcp…
mobiai-kmp
Use when working on a Kotlin Multiplatform project — shared code, expect/actual declarations, platform-specific implementations, building and testing.
kotlin-concurrency-expert
Kotlin Coroutines review and remediation for Android. Use when asked to review concurrency usage, fix coroutine-related bugs, improve thread safety, or resolve lifecycle issues in Kotlin/Android code.
android-viewmodel
Best practices for implementing Android ViewModels using Kotlin 2.3+ Explicit Backing Fields, StateFlow for UI state, and SharedFlow for one-off events.